Dental instrument

ABSTRACT

An improved dental instrument for use in cleaning teeth, the instrument having a polishing cup with a self-contained abrasive and a system for automatically supplying a cooling fluid to the polishing cup when the cup is rotated; the cooling fluid serving the additional purpose of lubricating the cup driving mechanism, thereby eliminating the need of packing the driving mechanism in grease and allowing the instrument to be sterilized between uses.

BACKGROUND OF THE INVENTION

This invention relates to a novel dental hand piece for utilization inthe cleaning of teeth.

The most common method in widespread use today, among dentists, for thecleaning of teeth consists of the utilization of an abrasive polishingpaste in combination with a dental handpiece having a rotatableelastomeric polishing or prophy cup secured thereto. The paste isnormally carried or disposed in a relatively small jar or container andthe polishing cup is manually dipped into the supply of paste forcoating of the cup with the polishing or cleaning material. The coatedpolishing cup is then applied to the surface of the teeth and thehandpiece is actuated by the dentist's usual power equipment forrotating rotating the cup. This procedure of dipping the polishing cupinto the supply of paste and applying the coated cup to the surface ofthe teeth is not only time-consuming for the dentist but also the normalrotational speed of the coated cup causes the paste to be thrown fromthe cup due to centrifugal force. As a result, the polishing of theteeth is unduly time-consuming because of the constant dipping and thevisual obstruction of the tooth being cleaned by the paste and ofdiscomfort to both the patient and the dentist due to the paste beingthrown around.

In addition to the aforementioned disadvantages, the same dentalhandpiece is used over and over for all patients, thereby transferringgems from the mouth of one patient to the mouth of another. Obviously,it is a very unsanitary process to place the same dental instrument intothe mouths of different patients without sterilizing the instrumentbetween patients. Most dentists recognize that such a procedure is atbest unsanitary and fraught with danger but they have no choice in thematter since the head of the dental instrument, into which the polishingcup is inserted, has a number of gears therein which are caused torotate and the gears are packed in grease and sealed. If the dentisttried to sterilize the instrument the grease would break down and notperform its lubricating function and within a short period of time thegears would jam, thereby rendering the instrument inoperable.

SUMMARY OF THE INVENTION

The present invention overcomes the aforementioned problems by providinga dental instrument that can be used for the cleaning and polishing ofteeth without the need for constant dipping in a separate cup of pasteand the gears of which are lubricated by the same fluid that cools thetooth being cleaned. The invention consists of a polishing cup which isrotably secured to the head of the instrument; the cup is aself-contained polishing tool in that there is impregnated into theelastomeric material from which the cup is constructed an abrasivematerial. By providing a polishing cup which has its own supply ofabrasive material the utilization of a separate supply of paste iseliminated. Additionally, the driving gears within the head of theinstrument are lubricated by the fluid which is caused to passtherethrough into the polishing cup, thereby eliminating the necessityof packing the gears in grease and consequently allowing the instrumentto be sterilized between patients. The fluid is supplied to the cup froman independent source which is secured to the instrument and provisionis made to regulate the flow of the fluid in proportion to the rotatingspeed of the cup so that as the cup's speed increases the amount offluid provided to cool the tooth being cleaned is increased.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a side elevation of a dental instrument;

FIG. 2 is a side elevation partially in section of one embodiment of thepresent invention;

FIG. 3 is a sectional plan view along line 3--3 of FIG. 2; and

FIG. 4 is a fragmentary view of an alternate embodiment of the presentinvention.

FIG. 5 is a side elevation partially in section of an alternateembodiment of the present invention.

FIG. 6 is a sectional view along line 6--6 of FIG. 5.

FIG. 7 is a side elevation in section of a supply cartridge utilized inthe present invention.

FIG. 8 is a fragmentary view of an alternate fluid metering system ofthe present invention

FIG. 9 is a sectional view along line 9--9 of FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, wherein the like reference numbersdesignate like or corresponding parts throughout the several views,there is shown in FIG. 1 a conventional dental instrument 10 to whichthe present invention may be incorporated as a built-in part thereof orcombined therewith as an attachment. In FIG. 1 there is shown the dentalinstrument 10 having a polishing cup 11 which is adapted to be rotatedby a pulley 12. The instrument 10 is supported by a bracket 13 whichextends from an articulated frame 14 on which is carried means forrotating the pulley 12 in a well known manner.

While a drive train as shown in FIG. 1 is typical with regard to dentalinstrument it is contemplated by the present invention that the dentalinstrument 10 can be made into a portable instrument which would have anindependent drive means. An alternate gas driven model is illustrated inFIG. 5 and is described in detail hereinafter. However in addition tothe embodiments illustrated in the various figures it also is intendedthat a dental instrument 10 which is driven electrically is encompassedby the present invention. In such an electrically driven instrument, abattery and an electrical motor would be incorporated within theinstrument and the instrument would be adapted to be pluged into anelectrical source in order to either recharge the battery or to directlydrive the motor. An illustration and detailed description of such anarrangement has not been provided herein since such a drive means iswell known in the art to which this invention pertains and in theinterest of brevity and clarity it is not warrented.

The instrument 10 of FIG. 2 basically consists of a hollow substantiallytubular handpiece 15 having a body portion 16 and a head portion 17. Thebody portion 16 has a chamber 18 extending therethrough and terminatingat an annular shoulder 19 adjacent the head portion 17. The head portion17 consists generally of a tubular member having an enlarged end 20, thetubular member of the head portion has a diameter smaller than thediameter of the body portion 16. Disposed longitudinally through thetubular member of the head portion 17 and terminating adjacent theenlarged end 20 is a channel 21 which is coaxial to the chamber 18.Extending through one end of the enlarged end 20 and terminatingadjacent its opposite end is an aperture 22 which intersects the channel21 in an orientation normal thereto and extends therebeyond to itstermination point.

Extending through the chamber 18 and the channel 21 in coaxiallongitudinal alignment to the body portion 16 and the head portion 17 isa shaft 23. The shaft 23 is secured on one end to a driving means andterminates in complementary relationship to the aperature 22 in theenlarged end 20 and is adapted to be rotated by the driving means.Disposed within the shaft 23 from its end adjacent the aperature 22 to apoint intermediate the ends of the head portion 17 is an orifice 24,which orifice is coaxial to the channel 21. Radiating outwardly from theend of the orifice 24 which terminates intermediate the ends of the headportion 17 are a plurality of vents 25 which extend through the shaft 23into communication with the channel 21, thereby providing a passagewayfrom the channel 21 to the aperature 22.

Secured to the shaft 23 within the channel 21 adjacent to the chamber 18and extending along the shaft to a point adjacent the vents 25 is aspiral screw pump 26. The screw pump 26 because of its attachment to theshaft 23, is adapted to rotate in conjunction with the shaft and isconfigured to draw material from the chamber 18 through the pump intothe channel 21 adajacent to the vents 25. A bevel gear 27 is secured tothe end of the shaft 23 along its end so that a portion of the bevelgear 27 extends into the aperature 22, the axis of rotation of the bevelgear 27 is coaxial to the axis of rotation of the shaft 23 and the screwpump 26. The shaft 23 is supported along its length within the channel21 by a bushing 28 which has an inner diameter slightly larger than theouter diameter of the shaft 23 so that the shaft is permitted to rotatewithin the bushing 28, but prevented from bending. The bushing 28 can beconstructed from any one of many materials which have a low coefficientof friction and a high strength.

The bushing 28 engages the shaft 23 along its length between the vents25 and the bevel gear 27 and is adapted to be rigidly secured in thechannel 21 in order that the bushing will remain in a fixed positionwhile the shaft 23 is allowed to rotate. The shaft 23 has an enlargedportion 29 intermediate the vents 25 and the bushing 28 tolongitudinally locate the shaft 23 in a fixed position in order toensure that the bevel gear 27 engages and remains in engagement with asecond bevel gear 30 which is disposed within the aperature 22 in normalrelationship to the bevel gear 27. The bevel gear 30 may be secured toor be an integral part of an arbor 31 which is journaled within theaperature 22 in a perpendicular relationship to the shaft 23. The arbor31 is adapted to be rotated in conjunction with the bevel gear 30 whenthe bevel gear 30 is caused to be rotated by the bevel gear 27 and theshaft 23. In effect, the bevel gear 27 is the driving gear and thesecond bevel gear 30 is the driven gear. A lock nut 32 is disposedwithin the open end of the aperature 22 and adapted to rotatably securethe arbor 31 within the aperature 22. Disposed longitudinally throughthe arbor 31 is an orifice 33, which orifice is intersected by aplurality of vents 34 which extend through the arbor 31 in coaxialcomplementary relationship to the orifice 24 of the shaft 23.

The polishing cup 11 has secured thereto a securing means 35 which isadapted to secure the cup 11 to the arbor 31 in a manner which allowsthe cup 11 to rotate in conjunction with the arbor 31 while allowing thecup 11 to be removed from the arbor for repair or replacement. Thesecuring means 35 has an aperature 36 which extends thererthrough incoaxial alignment with orifice 33 of the arbor 31.

In operation, a polishing cup 11 having the desired abrasive rating,which can be regulated by the amount and mesh size of the pumice orother abrasive imbedded in the cup, is secured to the arbor 31. Acartridge 37 which has a channel 40 extending longitudinallytherethrough is disposed within the chamber 18 so that the shaft 23extends through the channel 40 of the cartridge 37. The cartridge 37 isfilled with a fluid, such as glycerine, which has both cooling andlubricating characteristics and is provided with a pllurality ofopenings 38 which extend through the end of the cartridge 37 and allowthe glycerine to flow from the cartridge into the channel 21. A typicalcartridge 37 is shown in FIG. 7 from which it will be apparent that apiston 41 can be incorporated within the cartridge 37 to assist in theevacuation of the fluid contained therein. If desired the piston 41 canbe biased towards the openings 38 by a spring (not shown) or a source ofcompressed gas or any other well known means. In FIG. 7 it will be notedthat an additional opening 42 is located in the end wall of thecartridge 37 behind the piston 41 and if desired a pressure source canbe incorporated within the dental handpiece 15 to supply a pressure tothe backside of the piston 41 in order to move it forward. There areobviously many alternative methods of evacuating the fluid from thecartridge 37 such as a screw worm but since such means are well known inthe art a detailed description will not be included herein. Theoperator, upon energizing the drive means, causes the shaft 23 torotate, which in turn through the driving arrangement of the bevel gears27 and 30 causes the arbor 31 and the polishing cup 11 to rotate. As theshaft 23 rotates the screw pump 26 draws the cooling fluid from thecartridge 37 and forces it into the channel 21 adjacent the vents 25.The fluid in the channel 21 is caused to enter the vents 25 and flowthrough the orifice 24 in the shaft 23 and exit into the aperature 22 ofthe enlarged end 20, by the pressure of the fluid behind it, bycapillary action and other physical phenomena. Upon entering theaperature 22, the fluid passes around the arbor 31 and over the bevelgears 27 and 30, thereby lubricating and cooling the moving parts, andinto the vents 34 of the arbor 31. The fluid entering the vents 34passes through the orifice 33 of the arbor and aperature 36 of thepolishing cup securing means 35 to enter into the polishing cup 11 wherecentrifugal force causes the fluid to spread evenly along the entireinner surface of the cup. As can be seen from the description of theoperation of the instrument, the fluid is caused to pass from its supplysource through the instrument itself into contact with all moving parts,thereby providing the necessary cooling and lubricating of the movingparts and especially the gearing arrangement and thence into theself-contained polishing cup where the same fluid which lubricates thegears is used to cool the teeth being cleaned. If desired the fluid usedfor the cooling and lubricating can have various medicinal or cosmeticadditives dispersed therein, for example it might be advantageous to adda flavoring agent to the fluid or a floride solution so that in additionto providing a pleasant taste the teeth may be medically treated.Obviously the various types of additives that can be incorporated in thefluid supply are almost endless and an exhaustive recitation would serveno purpose.

FIG. 4 illustrates an alternate embodiment of the present invention,wherein a metering tube 39 is disposed in the closed portion of theenlarged end 20 in a manner such that the tube 39 is in communicationwith the orifice 33 of the arbor 31. In this embodiment the fluid iscaused to pass through the tube 39 from a source (not shown) in a rateproportional to the rotational speed of the arbor and then pass throughthe orifice 33 and the aperature 36 into the polishing cup 11. A portionof the fluid is caused to pass outwardly through the vents 34 bycentrifugal force and thereby coontact and lubricate the gears 27 and 30and arbor 31. In such an embodiment it is not necessary to provide acartridge 37, pump 26 or attendent passageways to take the fluid fromthe body of the instrument to the end 20.

An alternate embodiment of the dental instrument 10 wherein the coolingfluid is a gas is shown in FIG. 5. The dental instrument of thisembodiment which is shown partially in section is of a unitary design inthat it has a self-contained power, lubricating and cooling means. Itwill be noted that the enlarged end portion 20 has not been cut away,the reason being that the arrangement of parts therein is essentiallythe same as shown in FIG. 2 including the gearing arrangement.

In FIG. 5 the body portion 16 terminates in an open end to which issecured an end cap 43. The end cap 43 can be secured to the body portion16 in any one of many known ways, the only restriction being that theend cap 43 should be easily removable and replaceable as desired.Disposed centrally through the end cap 43 and adapted to belongitudinally adjusted is a speed adjusting means 44 which in theillustrated embodiment is shown as a thumb screw threadably securedthrough the end cap. Disposed within the chamber 18 of the body portion16 is a cartridge 45, the cartridge is maintained in a fixed positionwith regard to rotational movement by a detent 46 which is shown as akey disposed within the wall of the chamber 18 and adapted to mate witha longitudinal groove in the cartridge 45, however the detent can be aspring biased ball or any other mechanism which would prevent rotationalmovement.

The cartridge 45 differs from the cartridge 37 of FIG. 7 in that thecartridge 37 is adapted to contain and dispense a liquid while thecartridge 45 is adapted to contain and dispense a gas. In effect thecartridge 45 is similar to what is commonly known as a aerosal can inthat a gas is contained therein under pressure and a valve is arrangedin one end to provide a controlled release of the contained gas. Whenthe cartridge 45 is inserted within the chamber 18 and the end cap 43 issecured to the body portion 16 the valve 47 is brought into abutmentwith the end of a shaft 48. When the speed adjusting means 44 is fullyretracted the valve 47 of the cartridge 45 resides in its fully extendedor closed position and the cartridge 45 is sealed and the gas containedtherein is prevented from being released. When it is desired to releasethe gas the means 44 is caused to enter the chamber 18 where it contactsthe sealed end of the cartridge and forces the valve 47 into contactwith the end of the shaft 48. As the cartridge is forced further intothe chamber the shaft 48 causes the valve 47 to retract thereby allowingthe gas in the cartridge to be released. The further the cartridge 45 isforced into the chamber 18 by the means 44 the more the valve 47 isretracted by the shaft 48 and the greater the amount of gas that isreleased. When it is desired to terminate the flow of gas the means 44is retracted from the chamber and the spring biased valve 47 returns toits sealing position. In other words the speed adjusting means 44 byregulating the depth of penetration of the cartridge 45 into the chamberregulates the opening of the valve 47 and consequently the volume of gasreleased. The cartridge 45 is biased towards the means 44 by a spring 49which is positioned within the chamber 18 between the annular shoulder19 and the cartridge 45 in surrounding disposition to the shaft 48.

The shaft 48 extends longitudinally through the head portion 17 and isadapted to drive the arbor 31 in the same manner as the shaft 23 of FIG.2. The primary distinction between the shaft 48 and the shaft 23 is thatthe shaft 48 in addition to providing means for allowing the lubricatingand cooling fluid to pass through the bevel gears into the cup 11 alsohas a self-contained driving means adapted to rotate the shaft inresponse to the release of gas from the cartridge 45. The shaft 48 has alongitudinal channel 50 which originates at its end which is in contactwith the valve 47 and extends longitudinally through the shaft to apoint within the channel 21 of the head portion 17. The channel 50terminates at an enlarged portion of the shaft which serves as a turbinereaction wheel 51. The turbine wheel 51 is illustrated in greater detailin FIG. 6 wherein it can be seen to have a pair of opposed dischargevents 52 which radiate outwardly from the channel 50. Disposed betweenthe turbine wheel and the enlarged end 20 the shaft 48 is provided withvents 25 interconnecting with a longitudinal orifice 24 in the samemanner as shaft 23 of FIG. 2.

In operation the end cap 43 is removed and the cartridge 45 is insertedwithin the chamber 18. The end cap 43 is then replaced and the speedadjusting means 44 is screwed inwardly forcing the valve 47 intoengagement with the end of the shaft 48. As the shaft 48 depresses thevalve 47 the gas contained within the cartridge 45 is released andenters the channel 50 at a high velocity. The gas passes through thechannel 50 into the turbine wheel 51 where it imparts a rotational forceto the shaft 48 in a manner similar to a turbine as it exits through thedischarge vents 52. The rotational movement developed by the turbinewheel 51 causes the shaft 48 to rotate which through its drive traincauses the polishing cup 11 to rotate. The gas after exiting through thedischarge vents 52 into the channel 21 is caused to enter the vents 25and pass through the orifice 24 in the shaft 48 and exit into theaperature 22 of the enlarged end 20. Upon entering the aperature 22, thegas passes around the arbor 31 and over the bevel gears 27 and 30,thereby lubricating and cooling the moving parts and into the vents 34of the arbor 31. The gas entering the vents 34 passes through theorifice 33 of the arbor and aperature 36 of the polishing cup securingmeans 35 to enter into the polishing cup 11 whereupon it impinges uponthe tooth being cleaned and cools such tooth. It will be noted from theabove description of its operation that the gas upon exiting from theturbine wheel 51 follows an identical path as the fluid in the operationof the embodiment of FIG. 2. It is well known that there are many inertgases which are capable of lubricating moving parts and of cooling suchparts and any other elements that it may contact and therefore acomplete recitation of such gases will not be presented, however onesuch gas would be nitrogen.

Another embodiment which can be adapted to work in conjunction with theembodiment of FIG. 2 is illustrated in FIG. 8 where there is shown asection of the body portion 16. Disposed within the chamber 18 of thebody portion 16 is a cartridge 53 which can be filled with a lubricatingand cooling fluid such as glycerine. Slidably disposed within thecartridge 53 is a piston (not shown) which can be biased by a spring orother means to cause the fluid within the cartridge to discharge throughthe orifice 54. Rotatably disposed through the cartridge 53 is a shaft55 which has secured thereto adjacent the orifice 54 a metering disc 56.The metering disc 56 is of an annular construction and has an aperature57, which aperature is not in alignment with the orifice 54. The disc 56is adapted to rotate in conjunction with the shaft 55 and is positionedbetween the end of the cartridge 53 which contains the orifice 54 andthe shoulder 19 of the body portion 16. An annular member 58 is fixedlydisposed within the body portion 16 between the disc 56 and the shoulder19, the member having a passageway 59 which is complementary to theaperature 57 of the disc 56 at one end and complementary to the vent 25in the shaft 55 at its other end.

In operation, when the shaft 55 is rotated the disc 56 is caused torotate in conjunction with the shaft, however if desired the disc 56 canbe secured to the shaft 55 by a slight friction fit so that the discwill not have the same revolutions per minute (RPM) as the shaft butwill have a predetermined amount of slippage which will cause the disc56 to rotate at a lesser percentage of the shaft's rotation. Regardlessof which arrangement is utilized, as the disc 56 rotates, the aperature57 picks up a predetermined amount of fluid from the cartridge 53. Aswill be noted from FIG. 8, the disc 56 is spaced from the end of thecartridge 53 which contains the orifice 54 and as the fluid within thecartridge discharges through the orifice it flows into the space wherethe aperature 57 of the disc 56 picks up a metered portion. As the disccontinues to rotate the aperature 57 comes into complementaryrelationship with the passageway 59 of the member 58 at which time thefluid is transferred from the aperature 57 to the passageway 59 fromwhich it flows through the passageway into the vents 25. After entryinto the vents 25 the fluid passes through the shaft to the drive trainand thence to the polishing cup in the same manner as set forth withrespect to the embodiment of FIG. 2.

As will be obvious to those skilled in the art to which this inventionpertains, the cartridge of the emodiment of FIGS. 2 or 8 is notabsolutely necessary since the fluid contained in the cartridge can bejust as well contained in the chamber 18 of the body portion 16 and thena metering device such as the disc 56 can be utilized to transport apredetermined amount of fluid from the chamber to the vents of the shaftand thence through the drive train to the polishing cup.

As will be obvious from the above description, the present inventionprovides a number of major improvements over the existing prior artdevices. Some of the more obvious improvements are the self-lubricatingfeature, wherein the gears no longer need to be packed in grease andtherefore the instrument can be sterilized between uses; the eliminationof the need to continuously dip the polishing cup into a separate supplyof polishing paste and its consequent loss of time and efficiency,because now the polishing cup itself contains its own polishingabrasive; the elimination of possible burns due to lack of polishingpaste, which has its cooling agent contained therein, because with thepresent device the cooling fluid is continuously and automaticallysupplied to the polishing cup whenever the cup is rotated and theelimination of the mess caused by the supplemental paste being thrownabout by the rotating cup.

It is contemplated by the present invention that the fluid which servesto lubricate the driving means and provide a cooling film to thepolishing cup can also serve an additional purpose in actually cleaningthe teeth. Under normal conditions the teeth are cleaned by an abrasiveeither added to the cup or embedded therein as hereinbefore described,however it is entirely feasible to incorporate an additive into thefluid which additive would chemically remove the stains and tartar fromthe teeth. While almost any fluid can perform the function of cleaningto various degrees it is desirable in the present invention to utilize afluid which is not abrasive in order that the gears in the driving meansare not damaged, however such fluid must still be capable of lubricatingand cooling in addition to its cleaning. One such additive is a solutionof soap which in effect assists in the lubricating and also performs acleaning function. If such a combination lubricating, cooling andcleaning fluid is used then it is entirely possible to utilize apolishing cup with no abrasive therein.

From a detailed consideration of this description, it will be apparentto those skilled in the art that this invention may be employed orconstructed in a number of different ways through the use of routineskill in this field. For this reason, the present invention is not to beconsidered as being limited except by the appended claims defining theinvention.

We claim:
 1. In a dental instrument for cleaning teeth, including a handpiece and a power means, the improvement comprising:a polishing cuphaving an abrasive material embeded therein, said cup rotatively securedto said handpiece; driving means disposed within said handpiece andadapted to transfer energy from the power means to said polishing cup,whereby said cup is rotated when the power means is actuated, saiddriving means having a passageway extending therethrough incommunication with the internal surface of said cup; and means forsupplying a flow of fluid through said driving means into said cup saidmeans comprising a pump secured to said driving means and adapted torotate in conjunction therewith whereby fluid is drawn by said pump froma reservoir and deposited into the passageway in said driving means incommunication with the internal surface of said cup, whereby the fluidlubricates said driving means and provides a cooling film to theinternal surface of said cup.
 2. A dental instrument in accordance withclaim 1 wherein said means for supplying a fluid through said drivingmeans into said cup comprises an interconnected passageway extendingthrough said shaft into communication with said first and second gearsand said arbor and through said arbor and said securing means intocommunication with the inner surface of said cup.
 3. A dental instrumentin accordance with claim 1 further comprising a metering member disposedbetween said reservoir of fluid and said means for supplying a flow offluid whereby said metering member limits the flow of fluid from saidreservoir to said supplying means.
 4. A dental instrument in accordancewith claim 3 wherein said metering member comprises a disc having ametering orifice therein, said disc adapted to be rotated and provideintermittent communication between said reservoir and said supplyingmeans.
 5. A dental instrument in accordance with claim 1 wherein saidresevoir comprises a cartridge.
 6. A dental instrument in accordancewith claim 5 further comprising:a piston slidably disposed within saidcartridge; and means for biasing said piston into said fluid, wherebysaid fluid is urged out of said cartridge.